1. Field of the Invention
The present invention relates to a method for manufacturing a liquid jet recording head whereby to produce a resin ceiling plate by means of grooving, drilling, or the like using laser beams. The invention also relates to a liquid jet recording head.
2. Related Background Art
The liquid jet recording head, which is used for recording or printing on a recording medium (a recording paper sheet or the like) by discharging recording liquid (ink) from fine discharge openings (orifices) as flying droplets, is provided with a substrate (heater board) having a plurality of electrothermal transducing devices and lead electrodes therefor. It has been practiced, in general, that a resin nozzle layer (liquid flow path formation layer) that forms liquid flow paths (nozzles) and a common liquid chamber is laminated on the substrate, and then, a glass ceiling plate, which is provided with recording liquid supply tubes, is overlaid on such layer. In recent years, however, the glass ceiling plate is omitted. Here, a resin ceiling plate is formed instead by an injection molding or the like together with the recording liquid supply tubes in addition to the liquid flow paths and the common liquid chamber. Then, after discharge openings are processed, the ceiling plate is pressed to the substrate by means of an elastic member. In this way, an integrated liquid jet recording head has been developed. Such liquid jet recording head makes it possible to reduce the number of parts to be assembled, simplifying the assembling steps significantly, thus contributing to reducing the cost of manufacture remarkably.
FIG. 3 is a partly broken perspective view which shows the resin ceiling plate, illustrating the fundamental mode of a liquid jet recording head Eo using the resin ceiling plate. The liquid jet recording head Eo comprises a substrate 1001 provided with a plurality of electrothermal transducing devices 1001a, and a resin ceiling plate 1002 provided with liquid flow paths 1002a positioned on each of the electrothermal transducing devices 1001a, and a common liquid chamber 1002b conductively connected with them. For the resin ceiling plate 1002, there are formed integrally a discharge opening plate 1002d having discharge openings 1002c which are conductively connected with each of the liquid flow paths 1002a, and a cylindrical extrusion 1002f having a liquid supply opening 1002e which is open to the common liquid chamber 1002b.
The resin ceiling plate 1002, which is provided with the discharge opening plate 1002d and the cylindrical extrusion 1002f in addition to the liquid flow paths 1002a and the common liquid chamber 1002b, is integrally formed by means of an injection molding or the like. Then, after discharge openings 1002c are processed to be formed, the ceiling plate 1002 is pressed onto the substrate 1001 by means of an elastic member (not shown), while the liquid flow paths 1002a are positioned on the electrothermal transducing devices 1001a, respectively. Then, these members are bonded altogether. The substrate 1001 is fixed to the base plate 1004 by means of screws or some other known methods together with the circuit board 1003 having driving circuits arranged on it to generate electric signals transmitted to each of the electrothermal transducing devices 1001a.
Also, a work (roughly molded product), which comprises the main body portion before the provision of liquid flow paths 1002a, the discharge opening plate 1002d before the provision of the discharge openings 1002c, and others, is integrally formed by means of an injection molding. Then, using excimer laser beams the liquid flow paths 1002a are grooved on the main body portion of the resin ceiling plate 1002, and likewise, each of discharge openings 1002c is formed on the discharge opening plate 1002d by drilling using the excimer laser beams as well. In this way, a method for manufacturing the resin ceiling plate 1002 has been developed.
By the combination of the injection molding and the laser processing such as described above, it is possible to produce the resign ceiling plates at lower costs, thus promoting the manufacture of liquid jet recording heads at lower costs. In this respect, the laser processing apparatus, which performs the irradiation of excimer laser beams to form grooves and holes on the work that has been obtained by the injection molding, is generally provided with a mask having the opening patterns for the formation of the liquid flow paths and discharge openings of a liquid jet recording head, and also, with a projection optical system that enables the opening patterns of the mask to be projected on the work using the excimer laser beams.
For the laser processing equipment that uses the mask, a laser drilling apparatus has been applied for patent, such as in Japanese Patent Laid-open Application No. 5-111782, where a mechanism is provided for executing periodical sampling inspections to reset the laser power and its irradiation period or to adjust mask positions in order to obtain highly precise configuration and dimension with respect to the work.
However, when a plurality of liquid flow paths and discharge openings are processed on an injection molded work for the formations thereof altogether by means of laser processing using the conventional technique described above, the energy of the excimer laser beams is concentrated on the work so that the surface temperature of the work may arrive at 100.degree. C. to 200.degree. C. while grooves or holes are being processed. As a result, the resin that forms the work tends to be expanded or contracted due to heat, which causes errors in the projection pitches of grooves or holes, and leads to reducing the yield of the products.
This in turn requires a complicated adjustment of processing pitches of the grooves or holes. It takes a long time to complete such complicated adjustment, presenting a problem that the operational efficiency is seriously affected.